New class of cobalt-free cathodes could enhance energy density of Li-ion batteries

Oak Ridge National Laboratory (ORNL) researchers have developed a new family of cathodes with the potential to replace the costly cobalt-based cathodes typically found in today’s lithium-ion batteries.

The new class, called NFA (nickel, iron, aluminum), is a derivative of lithium nickelate that’s used as a cathode material. These novel cathodes are designed to be fast-charging, energy-dense, cost-effective and longer-lasting.

Cobalt, which makes up a significant portion of the cost of current lithium-ion batteries, is largely mined overseas, often in controversial conditions. Finding an alternative material to cobalt that can be manufactured cost-effectively has become a priority of battery researchers.

ORNL scientists tested the performance of the NFA class of cathodes and determined that they are promising substitutes for cobalt-based cathodes, as described in Advanced Materials and the Journal of Power Sources. Researchers used neutron diffraction, Mossbauer spectroscopy and other advanced characterization techniques to investigate NFA’s atomic- and micro-structures as well as electrochemical properties.

“Our investigations into the charging and discharging behavior of NFA showed that these cathodes undergo similar electrochemical reactions as cobalt-based cathodes and deliver high enough specific capacities to meet the battery energy density demands,” said Belharouak.

Belharouak added that not only does NFA perform as well as cobalt-based cathodes, but the process to manufacture the NFA cathodes can be integrated into existing global cathode manufacturing processes.

“Lithium nickelate has long been researched as the material of choice for making cathodes, but it suffers from intrinsic structural and electrochemical instabilities,” he said. “In our research, we replaced some of the nickel with iron and aluminum to enhance the cathode’s stability. Iron and aluminum are cost-effective, sustainable and environmentally friendly materials.”

Source: ORNL